Radiation-curable metal particles and curable resin compositions comprising these particles

ABSTRACT

To provide a liquid curable resin composition which can produce transparent cured products with a high refractive index, high hardness, and superior abrasion resistance, and can be suitably used as a coating material.  
     [Solution] 
     A liquid curable resin composition comprising: (A) a poly-functional (meth)acrylic compound having at least three (meth)acryloyl groups in the molecule, (B) a reaction product obtained by the reaction of a compound having a polymerizable unsaturated group and alkoxysilyl group in the molecule and particles metal oxide, the metals being selected from the group consisting of zirconium, antimony, zinc, tin, cerium, and titanium, and (C) a radiation polymerization initiator.

FIELD OF THE INVENTION

[0001] The present invention relates to radiation-curable metalparticles comprising a radiation-curable group linked by a silyl groupto a metal and, to a liquid curable resin composition comprising apoly-functional (meth)acrylic compound and these metal oxide particles.More particularly, the present invention relates to a liquid curableresin composition which can produce cured products with a highrefractive index by application to fabricated plastic articles or filmsand can also produce anti-reflection films.

BACKGROUND OF INVENTION

[0002] Conventionally, a hard coat treatment has been applied as meansfor protecting surfaces of fabricated plastic materials such as plasticoptical parts, touch panels, and film-type liquid crystal elements, aswell as coated surfaces such as floors and walls inside buildings. UVcurable acrylic-type hard coat materials such as polyester acrylate,urethane acrylate, and epoxy acrylate have been used as such hard coatmaterials. When used alone, however, these hard coat materials could notsufficiently improve mar resistance, slip characteristics, and stainresistance of the above-mentioned plastic surfaces and coated surfaces.

[0003] A method of adding inorganic fillers such as silica or organicfillers such as polyethylene powder and polycarbonate powder and amethod of adding additives such as silicone are well known as the methodfor improving mar resistance, slip characteristics, and stain resistanceof fabricated plastic surfaces.

[0004] However, the method of adding inorganic or organic fillers hasdrawbacks such as an increased haze value and impaired appearance ofresulting coating films. The method of adding silicone can improve slipcharacteristics of coating surfaces, but not mar resistance due toabrasive wheels. In addition, a hard coat applied to a touch panel orthe like requires an after-treatment step with alkali etching. This mayinvolve hydrolysis of commonly used silicone additives with alkali,resulting in impaired appearance of coatings or peeling of coatings fromfabricated plastic materials.

[0005] With regard to a thermosetting resin material with a highrefractive index, Japanese Patent Publication No. 12489/1990 discloses ahigh refractive index resin used for lenses. The resin comprises apolymer obtained by the reaction of a vinyl compound and an urethanized(meth)acrylic monomer which is obtained by the reaction of a(meth)acrylic monomer having a halogen substituted aromatic ring and apolyfunctional isocyanate compound. Although the resin has a highrefractive index, its abrasion resistance is insufficient.

[0006] On the other hand, with regard to a photopolymerizablecross-linking coating materials, Japanese Patent Application Laid-openNo. 169833/1987 discloses a photocurable monomer comprising polyacrylateof dipentaerythritol. Coatings with sufficient hardness can be obtainedin a short period of time using this monomer. However, because thecoatings have a refractive index of 1.55 or less, the monomer mayproduce interference stripes if coated over the substrate with a highrefractive index such as polycarbonate, polyester carbonate,polyethylene terephthalate, or poly-1,4-cyclohexane dimethyleneterephthalate. Thus, this material is inadequate for use with opticalproducts requiring high resolution.

PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] An object of the present invention is to provide a liquid curableresin composition which can produce transparent cured products with ahigh refractive index, high hardness, and superior abrasion resistance,and can be suitably used as a coating material.

[0008] Another object of the present invention is to provide a liquidcurable resin composition suitable for producing a hard coat over thesurface of fabricated plastic materials.

[0009] Other objects and features of the present invention will becomeapparent from the following detailed description of the presentinvention.

SUMMERY OF THE INVENTION

[0010] The present invention provides radiation-curable metal particlescomprising a radiation-curable group linked by a silyl group to a metal,in particular where said metal is not inclusive of silicon metal. Alsoprovided are methods to prepare such particles.

[0011] In addition, the present invention provides compositions thatcomprise the above-noted particles. Preferred compositions provided bythe present invention are compositions that, after radiation cure,provide products of high transparency, low haze, and a refractive indexof more than 1.55.

[0012] Furthermore, the present invention provides articles made bycuring the above compositions, including articles comprising coatingsand films formed from such compositions. In particular articles havingantireflection properties are provided.

DETAILED DESCRIPTION OF THE INVENTION

[0013] Herein certain terms are used to define certain chemical aspects.These terms are defined below.

[0014] A (meth)acrylic compound is a compound comprising a(meth)acryloyl group, whereby it is noted that a (meth)acrylol group, bydefinition, comprises an unsaturated bond.

[0015] When reference is made to groups in the periodic table ofelements, reference is made to the periodic table appearing on theinside front cover of “CRC Handbook of Chemistry and Physics”, 78th ed.1997-1998, and to the “New Notation” noted thereon.

[0016] Consequently, the groups are numbered in arabic notation, forexample group 11 is the group consisting of copper, silver and gold,group 2 is the group that includes magnesium, calcium and barium etc.Furthermore, in this application, group 3 is considered to includeelements 57-71 and elements 89-103, i.e. the lanthanides and actinides.

[0017] The present invention provides a radiation-curable metal particlecomprising a radiation-curable group linked by a silyl group to a metal,which hereinafter will also be referred to as “component B”. It will beappreciated by one of ordinary skill in the art that “component B” mayrefer to a single particle, multiple particles, or a mixture ofparticles.

[0018] The present invention further provides compositions comprisingthese particles. Such radiation-curable compositions may be any suitableradiation-curable composition, and may further comprise a (meth)acryliccompound (hereinafter also referred to as “component (A)”). Thecomposition may, independent of the presence of component (A), alsocomprise a radiation polymerization initiator (hereinafter also referredto as “component (C)”).

[0019] Component (A) can be any suitable (meth)acrylic compound.Preferably, component(A) comprises at least three (meth)acryloyl groupsin the molecule, more preferably from 3 to 10 (meth)acryloyl groups,even more preferably from 4 to 10 (meth)acryloyl groups, and mostpreferably from 4 to 8 (meth)acryloyl groups.

[0020] Given as examples of such a (meth)acrylic compound aretrimethylolpropane tri(meth)acrylate, trimethylolpropane trioxyethyl(meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate,pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate,dipentaerythritol hexa(meth)acrylate, and the like.

[0021] As examples of commercially available products of the(meth)acrylic compound having at least three (meth)acryloyl groups inthe molecule, Kayarad DPHA, DPCA-20, DPCA-30, DPCA-60, DPCA-1 20, D-310,D-330, PET-30, GPO-303, TMPTA, THE-330, TPA-330 (manufactured by NipponKayaku Co., Ltd.), Aronix M-315, M-325 (manufactured by Toagosei Co.,Ltd.), and the like can be given.

[0022] The proportion of the (meth)acrylic compound having at leastthree (meth)acryloyl groups in the molecule used as the component (A) inthe composition of the present invention is in the range preferably from1 to 99 wt %, more preferably from 10 to 90 wt %, and particularlypreferably from 30 to 70 wt %. The number of (meth)acryloyl groups inthe molecule is preferably from 4 to 10, and more preferably from 4 to8.

[0023] The particles of component (B) comprise a radiation-curable grouplinked by a silyl group to a metal. The metal can be any suitable metal,and is preferably a metal selected from the metals listed in groups 2-16from the periodic table of elements exclusive of silicon metal.Preferably the metal is selected from the metals listed in groups 3-4and 12-15 from the periodic table of elements (exclusive of siliconmetal). In particular it is preferred that the metal is selected fromthe group consisting of zirconium, titanium, antimony, zinc, tin,indium, cerium and aluminium, and most preferably the metal is selectedfrom the group consisting of zirconium, antimony, zinc and cerium.

[0024] The silyl group is preferably a substituted silyl group. Thesubstituted silyl group may be any suitable silyl group. Preferably, thesubstituted silyl group comprises a urethane group, a thiorethane groupand/or an alkoxy group. Preferably, the silyl group comprises at least aurethane group.

[0025] The silyl group may be derived from compounds having at least onealkoxysilyl group and mercapto group in the molecule, as noted hereinbelow, and such compounds reacted with the isocyanates noted hereinbelow.

[0026] In a composition that comprises both component (A) and component(B), the proportion of component (B) is preferably from 1 to 99 wt %,more preferably from 10 to 90 wt %, and particularly preferably from 30to 70 wt %, relative to the total weight of the composition.

[0027] When component (B) is a mixture of particle 5, preferably atleast 90 wt %, more preferably at least 95%, and most preferably atleast 99 wt % of the total metals (excluding the silicon in the silylgroup) in component (B) is selected from the group consisting ofzirconium, titanium, antimony, zinc, tin, indium, cerium and aluminium.

[0028] Component (B) may be a reaction product.

[0029] The reaction product used as the component (B) is obtained by thereaction of an organosilicon compound having a polymerizable unsaturatedgroup and alkoxysilyl group in the molecule and metal oxide particles,wherein the major components of metal oxide particles are oxide ofmetals selected from the group consisting of zirconium, titanium,antimony, zinc, tin, indium, cerium, and aluminum. The proportion of thereaction product contained in the composition of the present inventionas the component (B) is preferably from 1 to 99 wt %, more preferablyfrom 10 to 90 wt %, and particularly preferably from 30 to 70 wt %. Thereaction is carried out preferably in the presence of water.

[0030] The reaction product used as the component (B) in the presentinvention can be prepared by a method including at least an operation ofmixing the organosilicon compound and metal particles. The amount ofresidual organosilicon compounds immobilized on metal oxide particles ispreferably 0.01 wt % or more, more preferably 0.1 wt % or more, and mostpreferably 1 wt % or more. If the amount of residual organosiliconcompounds immobilized on metal oxide particles is less than 0.01 wt %,dispersibility of the reaction product containing metal oxide particlesin the composition of the present invention may be insufficient, whichmay result in lack of transparency and abrasion resistance of thecomposition. The proportion of organosilicon compounds in the rawmaterial composition to produce the component (B) is preferably 10 wt %or more, and more preferably 30 wt % or more. If proportion oforganosilicon compounds is less than 10 wt %, film-forming capability ofthe resulting composition may be poor. The proportion of metal oxideparticles in the raw material composition for the component (B) ispreferably 50 wt % or less, and more preferably 20 wt % or less.Dispersibility, transparency, and abrasion resistance of the resultingcomposition may be insufficient, if the amount of the metal oxideparticles in the raw material composition for preparing component (B) ismore than 50 wt %.

[0031] Preferably the organosilicon compound possesses a polymerizableunsaturated group and alkoxysilyl group in the molecule. As preferableexamples of the polymerizable unsaturated group, acrylic group, vinylgroup, and styryl group can be given. As an alkoxysilyl group, the groupwhich can be hydrolyzed in the presence of water or a hydrolysiscatalyst is desirable. In addition, the organosilicon compound maycontain at least one bond selected from an ester group, ether group,urethane group, sulfide group, and thiourethane group in the molecule.The organosilicon compound preferably comprises at least onepolymerizable unsaturated group, urethane bond group, and alkoxysilylgroup as its constituents. The alkoxysilyl group is the component whichcombines with adsorption water existing on the surface of metal oxideparticles by a hydrolysis-condensation reaction. The polymerizableunsaturated group is the component of which the molecules chemicallycross-link among themselves by an addition polymerization reaction inthe presence of reactive radicals. The urethane bond group is aconstitutional unit which bonds the molecules having an alkoxysilylgroup and the molecules having a polymerizable unsaturated groupdirectly or via other molecules. At the same time, the urethane bondgroup creates a moderate cohesive force among molecules due to hydrogenbonds, thereby providing the cured products made from the composition ofthe present invention with excellent mechanical strength, superioradhesion with substrates, high heat resistance, and the like.

[0032] As examples of preferable organosilicon compounds, the compoundsshown by the following formula (1) can be given.

[0033] wherein R¹ is a hydrogen atom or a mono-valent organic grouphaving from 1 to 8 carbon atoms, such as methyl, ethyl, propyl, butyl,phenyl, or octyl group; R² is a hydrogen atom or an alkyl group havingfrom 1 to 3 carbon atoms; and m is 1, 2 or 3. As examples oftrimethoxysilyl groups represented by the formula, (RO¹)_(m)R² _(3−m)Si,triethoxysilyl group, triphenoxysilyl group, methyldimethoxysilyl group,dimethylmethoxysilyl group, and the like can be given, with preferredgroups being trimethoxysilyl group and triethoxysilyl group. Astructural unit represented by the formula,—(C═O)NH—R⁴—NH(C═O)O—X—O]_(p)—, is introduced to extend the molecularchain into the structure shown by the above-mentioned formula (1). R³ isa divalent organic group having from 1 to 3 carbon atoms. R⁴, which maybe either the same with or different from R³, is a divalent organicgroup and selected from divalent organic groups with a molecular weightfrom 14 to 10,000, preferably from 78 to 1,000, for example, a linearpolyalkylene group such as methylene, ethylene, propylene,hexamethylene, octamethylene, and dodecamethylene groups; alicyclic orpolycyclic divalent organic groups such as cyclohexylene andnorbornylene groups; divalent aromatic groups such as phenylene,naphthylene, biphenylene, and polyphenylene groups; and alkyl group oraryl group substitution products of these groups. These divalent organicgroups may further contain atomic groups containing elements other thancarbon atoms and hydrogen atoms. p and q in the above formula are 0or 1. X is a divalent organic group, and more particularly, a divalentorganic group originating from the compound having an active hydrogenatom which can react with an isocyanate group in the molecule by theaddition reaction. Given as examples are divalent organic groupsobtained by removing two active hydrogen atoms from the compound such asa polyalkylene glycol, polyalkylene thioglycol, polyester, polyamide,polycarbonate, polyalkylene diamine, polyalkylene dicarboxylic acid,polyalkylene diol, or polyalkylene dimercaptan. R⁵ is an organic groupwith a valency of (n+1). Such an organic group is preferably selectedfrom linear, branched, or cyclic saturated hydrocarbon groups,unsaturated hydrocarbon groups, and alicyclic groups. Y in the aboveformula represents a mono-valent organic group having a polymerizableunsaturated group which causes a cross-linking reaction to occur amongthe molecules in the presence of reactive radicals, such as, forexample, acryloxy group, methacryloxy group, vinyl group, propenylgroup, butadienyl group, styryl group, ethynyl group, cinnamoyl group,maleate group, acrylamide group, and the like. Among these, acryloxygroup is desirable. n is a positive integer preferably from 1 to 20, andmore preferably from 1 to 10, and particularly preferably from 3 to 5.

[0034] The organosilicon compound used in the present invention can beprepared, for example, by (1) an addition reaction of an alkoxysilanehaving a mercapto group (i.e. a mercaptoalkoxysilane), a polyisocyanatecompound, and an active hydrogen group-containing polymerizableunsaturated compound which possesses an active hydrogen which can causean addition reaction to occur with an isocyanate group; (2) a directreaction of an isocyanate compound having an isocyanate group and analkoxysilyl group in the molecule with an active hydrogen-containingpolymerizable unsaturated compound; or (3) an addition reaction of acompound having a polymerizable unsaturated group and an isocyanategroup in the molecules and a mercaptoalkoxysilane or aminosilanecompound.

[0035] The following methods can be given as examples of the methodusing a mercaptoalkoxysilane as a raw material.

[0036] Method (a):

[0037] A method comprising reacting a mercaptoalkoxysilane and apolyisocyanate compound to produce an intermediate which contains analkoxysilyl group, —S(C═O)NH— bonding group, and isocyanate group in themolecule, and reacting the isocyanate in the intermediate compound andan active hydrogen-containing polymerizable unsaturated compound tocombine this unsaturated compound via a urethane group.

[0038] Method (b):

[0039] A method of reacting a polyisocyanate compound and an activehydrogen-containing polymerizable unsaturated compound to produce anintermediate containing a polymerizable unsaturated group, urethane bondgroup, and isocyanate group in the molecule, and reacting thisintermediate with a mercaptoalkoxysilane to combine themercaptoalkoxysilane via a —S(C═O)NH— group.

[0040] In above-mentioned method (a) or (b), a linear, cyclic, orbranched compound having two or more active hydrogen atoms which isreactive with an isocyanate by an addition reaction in the molecule canbe used additionally. Such a compound can extend the length of the chainof the alkoxysilane compound obtained by the reaction with apolyisocyanate compound via a urethane bond.

[0041] The compounds having at least one alkoxysilyl group and mercaptogroup in the molecule can be given as examples of the alkoxysilane whichcan form the —S(C═2 O)NH— bond by the reaction with an isocyanate groupin the preparation of the compound shown by the above-mentioned formula(1).

[0042] Given as examples of such compounds are mercaptoalkoxysilanessuch as mercaptopropyltrimethoxysilane, mercaptopropyltriethoxysilane,mercaptopropylmethyldiethoxysilane, mercaptopropyldimethoxymethylsilane,mercaptopropylmethoxydimethylsilane, mercaptopropyltriethoxysilane,mercaptopropyltriphenoxysilane, and mercaptopropyltributoxysilane. Ofthese, preferable compounds are mercaptopropyltrimethoxysilane andmercaptopropyltriethoxysilane. As an example of commercially availablemercaptoalkoxysilane, SH6062 manufactured by Dow Corning Toray SiliconeCo., Ltd. can be given. These mercaptoalkoxysilanes can be used eitherindividually or in combinations of two or more. As othermercaptoalkoxysilanes, an addition product of an amino substitutedalkoxysilane and epoxy group substituted mercaptan, an addition productof an epoxy silane and α,ω-dimercapto compound, and the like can begiven.

[0043] The isocyanate compound used for preparing the organosiliconcompounds can be selected from the compounds having a linear saturatedhydrocarbon, cyclic saturated hydrocarbon, or aromatic hydrocarbonstructure. Such isocyanate compounds can be used either individually orin combinations of two or more. The number of isocyanate groups in amolecule is usually from 1 to 30, and preferably from 2 to 10. If morethan 30, the viscosity of the products increases, resulting in loweredprocessability. Given as examples of such a isocyanate compound arelinear hydrocarbon isocyanate compounds such as 3-trimethoxysilylpropaneisocyanate, 3-triethoxysilylpropane isocyanate, 3-methacryloxypropylisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, and2,2,4-trimethylhexamethylene diisocyanate; cyclic saturated hydrocarbonisocyanate compounds such as isophorone diisocyanate,dicyclohexylmethane diisocyanate, methylenebis (4-cyclohexylisocyanate),hydrogenated diphenylmethane diisocyanate, hydrogenated xylenediisocyanate, hydrogenated toluene diisocyanate, and1,3-bis(isocyanatemethyl) cyclohexane; and aromatic hydrocarbonisocyanate compounds such as 2,4-tolylene diisocyanate, 2,6-tolylenediisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate,p-phenylene diisocyanate, 3,3′-dimethyl-4,4′-diphenylmethanediisocyanate, diphenylmethane-4,4′-diisocyanate, 4,4′-biphenylenediisocyanate, 6-isopropyl-1,3-phenyl diisocyanate, 4-diphenylpropanediisocyanate, lysine diisocyanate, 1,5-naphthalene diisocyanate, andpolyisocyanates of polydiphenylmethane.

[0044] Among these, preferable compounds are cyclic saturatedhydrocarbon polyisocyanate compounds and aromatic hydrocarbonpolyisocyanate compounds, and more preferable compounds are cyclicsaturated hydrocarbon polyisocyanate compounds. Specific examples ofparticularly preferred polyisocyanate compounds are3-trimethoxysilylpropane isocyanate, 3-triethoxysilylpropane isocyanate,isophorone diisocyanate, hydrogenated xylene diisocyanate, andhydrogenated toluene diisocyanate. Given as examples of commerciallyavailable polyisocyanate compounds are A-1310 and Y-5187 manufactured byNippon Unicar Co., Ltd.; Calenz MOI manufactured by Showa Denko Co.,Ltd.; TDI-80/20, TDI-100, MDI-CR100, MDI-CR300, MDI-PH, and NDImanufactured by Mitsui-Nisso Urethane Co., Ltd.; Coronate T, MillionateMT, Millionate MR, and HDI manufactured by Nippon Polyurethane IndustryCo., Ltd.; and Takenate 600 manufactured by Takeda Chemical IndustriesCo., Ltd.

[0045] The amount of these polyisocyanate compounds used in theabove-mentioned method (a) is determined so that the ratio of theisocyanate group for one equivalent of the mercapto group in themercaptoalkoxysilane is in the range from 0.1 to 100 equivalent,preferably from 0.5 to 10 equivalent, and more preferably from 0.9 to1.2 equivalent. If the amount of the polyisocyanate compounds in termsof the equivalence of isocyanate group is less than 0.1, 0.9 equivalentof mercaptosilane may be left unreacted, giving rise to insufficientabrasion resistance of coating films. The use of polyisocyanatecompounds in excess of 100 equivalent of isocyante group may leave alarge amount of the isocyanate groups unreacted, resulting in thecomposition with lowered weather resistance.

[0046] In the above-mentioned method (b), on the other hand, the amountof the polyisocyanate compounds in terms of the equivalenct ofisocyanate group is in the range from 0.1 to 100, preferably from 0.5 to10, and more preferably from 0.9 to 1.2, for one equivalent of theactive hydrogen contained in active hydrogen-containing polymerizableunsaturated compounds.

[0047] In either the method (a) or method (b), a catalyst can be addedto shorten the reaction time. Either a basic catalyst or acid catalystcan be used as the catalyst. As examples of the basic catalyst, aminessuch as pyridine, pyrrole, triethylamine, diethylamine, dibutylamine,and ammonia; phosphines such as tributyl phosphine and triphenylphosphine; and the like can be given. Among these, tertiary amines suchas pyridine and triethylamine are desirable. As acid catalysts, metalalkoxides such as copper naphthenate, cobalt naphthenate, zincnaphthenate, 1,4-diazabicyclo[2.2.2]octane (DABCO), methyl DABCO,tributoxy aluminum, trititanium tetrabotoxide, and zirconiumtetrabotoxide; Lewis acids such as trifluoroboron diethyl etherate andaluminium chloride; tin compounds such as tin 2-ethylhexanoate, octyltin trilaurate, dibutyl tin dilaurate, octyl tin diacetate, and the likecan be given. Among these, acid catalysts are preferred, and tincompounds are particularly preferred. Specific examples of particularlypreferred tin compounds are octyl tin trilaurate, dibutyl tin dilaurate,octyl tin diacetate, and the like. The amount of these catalysts to beadded is from 0.01 to 5 parts by weight, and preferably from 0.1 to 1part by weight, for 100 parts by weights of polyisocyanate compounds.Effect of decrease in the reaction time is slight if the amount of thecatalyst added is less than 0.01 part by weight. On the other hand, whenthe amount of the catalyst is more than 5 parts by weight, storagestability of the product may be impaired.

[0048] As examples of the active hydrogen-containing polymerizableunsaturated compound which can bind with the above-mentionedpolyisocyanate compound through a urethane bond by the addition reactionin the preparation of the organosilicon compound, the compounds havingat least one active hydrogen atom which can form a urethane bond by theaddition reaction with an isocyanate group and at least onepolymerizable unsaturated group in the molecule can be given. Thesecompounds can be used either individually or in combinations of two ormore. Carboxylic acid group-containing polymerizable unsaturatedcompounds and hydroxyl group-containing polymerizable unsaturatedcompounds are given as such compounds. Specific examples ofpolymerizable unsaturated compound having a carboxylic acid groupinclude unsaturated aliphatic carboxylic acid such as (meth)acrylicacid, itaconic acid, cinnamic acid, maleic acid, fumaric acid,2-(meth)acryloxypropyl hexahydrogenphthalate, and 2-(meth)acryloxyethylhexahydrogenphthalate; and unsaturated aromatic carboxylic acid such as2-(meth)acryloxypropyl phthalate and 2-(meth)acryloxypropylethylphthalate. Given as examples of hydroxyl group-containing polymerizableunsaturated compounds are hydroxyl group-containing acrylates, hydroxylgroup-containing methacrylates, and hydroxyl group-containing styrenes,such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate,2-hydroxybutyl (meth)acrylate, 2- hydroxy-3-phenyloxypropyl(meth)acrylate, 1,4-butanediol mono(meth)acrylate, 2-hydroxyalkyl(meth)acryloyl phosphate, 4-hydroxycyclohexyl (meth)acrylate, neopentylglycol mono(meth)acrylate, poly(pentamethyleneoxycarboxylate)ethoxy(meth)acrylate, hdroxy styrene, hydroxy α-methylstyrene, hydroxyethylstyrene, hydroxy-terminal polyethylene glycol styryl ether,hydroxy-terminal polypropylene glycol styryl ether, hydroxy-terminalpolytetramethylene glycol styryl ether, terminal-hydroxy polyethyleneglycol (meth)acrylate, terminal-hydroxy polypropylene glycol(meth)acrylate, terminal-hydroxy poly(tetraethylene glycol(meth)acrylate), trimethylolpropane di(meth)acrylate, trimethylolpropanemono(meth)acrylate, ethlenoxide(EO)-modified trimethylolpropanetri(meth)acrylate, propylene oxide (PO)-modified trimethylolpropanetri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritoldi(meth)acrylate, pentaerythritol mono(meth)acrylate, dipentaerythritolpenta(meth)acrylate, dipentaerythritol tetra(meth)acrylate,dipentaerythritol tri(meth)acrylate, dipentaerythritol di(meth)acrylate,and dipentaerythritol mono(meth)acrylate.

[0049] Among these, unsaturated aliphatic carboxylic acids and hydroxylgroup-containing acrylate compounds are preferred, with the hydroxylgroup-containing acrylate compounds, such as, for example,2-hydroxylethyl acrylate, 2-hydroxypropyl acrylate, pentaerythritoltriacylate, and dipentaerythritol pentacrylate being particularlypreferred. The amount of these active hydrogen-containing polymerizableunsaturated compound in terms of equivalent of the active hydrogen isone equivalent or more for one equivalent of isocyanate group remainingin the intermediate compound which is produced by the addition reactionof a mercapto alkoxysilane and a polyisocyanate compound. If less thanone equivalent, the resulting composition may exhibit undesirableeffects such as foaming, viscosity increase, and coloring due to thereaction of reactive isocyanate groups remaining in the alkoxysilylcompound and moisture.

[0050] In the preparation of the organosilicon compound, with anobjective of improving flexibility of coating films and increasingadhesion with substrates, a divalent organic group may be introduced bythe addition reaction of a polyisocyanate compound between thealkoxysilyl group and the polymerizable unsaturated group. As theorganic compound which reacts with the isocyanate group by the additionreaction, a linear, cyclic, or branched organic compound having two ormore active hydrogen atoms in the molecule can be used. Here, asexamples of the group having active hydrogen atoms, a hydroxyl group,carboxyl group, mercapto group, amino group, sulfonic group, phosphoricacid group, silanol group, and the like can be given. These organiccompounds have two or more, preferably from 2 to 10, and more preferably2, active hydrogen atoms in the molecule. The molecular weight of thecompound having active hydrogen atoms is preferably from 50 to 100,000,more preferably from 100 to 50,000, and particularly preferably from 500to 10,000. As examples of such a divalent organic compound, polyalkyleneglycols, polyalkylene thioglycols, polyester diols, polyamides,polycarbonate diols, polyalkylene diamines, polyalkylene dicarboxylicacids, polyalkylene diols, and polyalkylene dimercaptans can be given.Among these, polyalkylene glycols are preferred. As examples ofcommercially available polyalkylene glycols, polyethylene glycol,polypropylene glycol, polytetraethylene glycol, polyhexamethyleneglycol, and copolymers of two or more of these polyalkylene glycols canbe given. Given as commercially available products are UNISAFE DC1100,UNISAFE DC1800, UNISAFE DCB1100, UNISAFE DCB 1800 manufactured by NipponOil and Fats Co. Ltd., PPTG 4000, PPTG 2000, PPTG 1000, PTG 2000, PTG3000, PTG 650, PTGL 2000, PTGL 1000 manufactured by Hodogaya ChemicalCo., Ltd., and EXCENOL 1020 manufactured by Asahi Glass Co., Ltd., PBG3000, PBG 2000, PBG 1000, Z3001 manufactured by Daiichi Kogyo SeiyakuCo., Ltd. The methods for preparing the polymerizable unsaturatedgroup-containing alkoxysilane containing the above-mentioned divalentorganic groups as the constituents will now be described takingpolyalkylene glycol as an example of the divalent organic groups.

[0051] Method (c):

[0052] A method comprising adding a polyalkylene glycol to the additioncompound of a mercapto alkoxysilane having a reactive isocyanate groupat the terminal thereof and a polyisocyanate compound to convert theterminal hydroxyl group into an alkoxysilane group, and reacting theresulting compound with a separately prepared addition compound of thepolymerizable unsaturated compound having a hydroxyl group at theterminal thereof and a polyisocyanate compound to combine them via aurethane bond.

[0053] Method (d):

[0054] A method of preparing an addition compound of a mercaptoalkoxysilane having a reactive isocyanate group at the terminal thereofand a polyisocyanate compound, and reacting this addition compound witha separately prepared another addition compound of a polyalkylene glycolpolyisocyanate compound having a reactive hydroxyl group at the terminalthereof and a hydroxyl group-containing polymerizable unsaturatedcompound, to combine these compounds via a urethane bond.

[0055] The conditions for forming the urethane bonds in the method (c)or method (d) are the same as the conditions used in the above-mentionedmethod (a) or (b). The equivalent ratio of the compound having ahydroxyl group at the terminal to the compound having a reactiveisocyanate group at the terminal taking part in the bonding is in therange preferably from 1.0 to 1.2. If less than 1.0, coloring andviscosity increase due to unreacted isocyanate group tend to occur.

[0056] Moreover, a co-hydrolyzate with other organic alkoxysilane may beused as the hydrolyzate of a polymerizable unsaturated group-modifiedalkoxysilane in the preparation of the alkoxysilane compound. Forexample, a co-condensation product with other organic alkoxysilane suchas an alkyl alkoxysilane, e.g. tetramethoxysilane, tetraethoxysilane,tetrabutoxysilane, methyltrimethoxysilane, methyltriethoxysilane,dimethyldimethoxysilane, phenyltrimethoxysilane, and the like may beused. When preparing the hydrolyzate, the amount of water used for thehydrolysis is usually from 0.5 to 1.5 equivalent for the amount of thetotal alkoxy group. A hydrolysis-condensation polymer can be obtained bystirring the reaction mixture for 5 minutes to 24 hours in the presenceor absence of solvent, while heating at a temperature from 0 to theboiling point of the components. In this instance, an acid catalyst orbase catalyst can be used to decrease the reaction time. The metal oxideparticles used for preparing the component (B) are in the form of fineparticles or a solvent dispersed sol. As a metal oxide, antimony oxide,zinc oxide, tin oxide, indium-tin mixed oxide, cerium oxide, aluminumoxide, titanium dioxide, and zirconium oxide can be given as examples.These may be used either individually or in combinations of two or more.In addition, from the viewpoint of ensuring mutual solubility anddispersibility with the component A and mutual solubility withphoto-initiators and photosensitizers, a sol in a polar solvent such asalcohol, dimethylformamide, dimethylacetamide, or cellosolve may be usedrather than water sol. As particularly preferred sols, sols of antimonyoxide, zinc oxide, cerium oxide, and zirconium oxide can be given.

[0057] The average diameter of metal oxide particles is, for example,from 0.001 to 2 μm. Such metal oxide particles can be commerciallyavailable under the tradenames such as Alumina Sol-100, -200, -520(alumina powder dispersed in water, manufactured by Nissan ChemicalIndustries, Ltd.), Celnax (zinc antimonate powder dispersed in water,manufactured by Nissan Chemical Industries., Ltd.), Nanotek (alumina,titanium oxide, tin oxide, indium oxide, and zinc oxide powdersdispersed in a solvent, manufactured by CI Chemical Co., Ltd.), TitaniaSol, SN-100D (a sol of antimony dope tin oxide powder dispersed inwater, manufactured by Ishihara Sangyo Kaisha, Ltd.), ITO powder(manufactured by Mitsubishi Material Co., Ltd.), Needral (cerium oxidepowder dispersed in water, manufactured by Taki Chemical Co., Ltd.), andthe like. To prepare transparent films using the composition of thepresent invention, a preferable particle diameter is in the range from0.001 to 2 μm, and more preferably from 0.001 to 0.05 μm. The form ofmetal oxide particles may be spherical, hollow, porous, rod-like,plate-like, fibrous, or amorphous, and preferably spherical. Thespecific surface area of metal oxide particles is preferably from 10 to3,000 m²/g, and more preferably from 20 to 1,500 m²/g. These metal oxideparticles can be used as dry powder or as a dispersion in water or anorganic solvent. Dispersions of fine particles of metal oxide well knownin the art as solvent dispersion sols of metal oxide, for example, canbe used as they are. The use of a solvent dispersion sol of metal oxideis particularly desirable to ensure transparency. Organic solvents whichcan be used as a dispersion medium for metal oxide include methanol,isopropyl alcohol, ethylene glycol, butanol, ethylene glycol monopropylether, methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene,dimethylformamide, and other solvents which are mutually soluble withthese organic solvent, as well as mixtures of these organic solvents andwater.

[0058] Preferable solvents are methanol, isopropyl alcohol, methyl ethylketone, xylene, and toluene.

[0059] The amount of alkoxysilane compound immobilized on the component(B) can be determined by measuring weight reduction (%) of the compoundwhen fine dry particles are completely burnt in the air by athermogravimetric analysis usually from room-temperature to 800.

[0060] The amount of water which is consumed by the hydrolysis ofalkoxysilane compounds in the preparation of the component (B) may beequivalent to the amount of water to hydrolyze at least one alkoxy groupon a silicon atom in the molecule. The amount of water to be added orpresent during the hydrolysis reaction is preferably ⅓ or more, and morepreferably from ½ to 3 times, for the number of mols of the total alkoxygroup on the silicon atoms. Only a product with the alkoxysilanecompound physically adsorbed on the surface of the metal oxide particlescan be obtained by merely blending the alkoxysilane compound of theabove-mentioned formula (1) and metal oxide particles under theconditions where there is completely no water. The effect of increasingabrasion resistance which is one of the objectives of the composition ofthe present invention cannot be exhibited using such materials as thecomponent (B).

[0061] The following methods can be used for preparing the component (B)of the present invention: a method comprising hydrolyzing thealkoxysilane compound of the above-mentioned formula (1), mixing thehydrolyzate with fine particles of metal oxide in the form of powder ora solvent dispersion sol, and stirring the mixture with heating; amethod of hydrolyzing the alkoxysilane compound of the above-mentionedformula (1) in the presence of the metal oxide particles; a method oftreating the surface of the metal oxide particles in the presence ofother components such as poly-functional unsaturated organic compounds,mono-functional unsaturated organic compounds, and photopolymerizationinitiators; and the like. Among these methods, a method of hydrolyzingthe alkoxysilane compounds shown by the above-mentioned formula (1) inthe presence of metal oxide particles is preferred. In the preparationof the component (B), a temperature from 20 to 150 and the treating timein the range from 5 minutes to 24 hours are applied.

[0062] The metal oxide particles are known to contain moisture on thesurface of the particles as adsorbed water during normal storageconditions. Therefore, it is possible to utilize the water contained inthe raw material in the preparation of the component (B) by mixing thealkoxysilane compound and metal oxide particles and stirring the mixturewhile heating.

[0063] When a powder of metal oxide fine particles is used in thepreparation of the component (B) of the present invention, an organicsolvent which is mutually soluble with water may be added to carry outthe reaction of the powder of metal oxide fine particles with thealkoxysilane compound homogeneous and smoothly. As preferable examplesof such an organic solvent, alcohols, ketones, ethers, and amides can begiven. Given as specific examples are alcohols such as methanol,ethanol, isopropyl alcohol, butanol, ethylene glycol monomethyl ether,and ethylene glycol monobutyl ether; ketones such as acetone, methylethyl ketone, and methyl isobutyl ketone; amides such asdimethylformamide, dimethylacetamide, N-methylpyrrolidone,γ-butyrolactone; and the like can be given. The amount of these solventsto be added is not specifically restricted inasmuch as such an amountconforms to the objective of carrying out the reaction smoothly andhomogeneously.

[0064] Moreover, an acid or a base may be added as a catalyst toaccelerate the reaction for the preparation of the component (B). Asexamples of the acid, inorganic acids such as hydrochloric acid, nitricacid, sulfuric acid, and phosphoric acid; organic acids such as methanesulfonic acid, toluene sulfonic acid, phthalic acid, malonic acid,formic acid, acetic acid, and oxalic acid; unsaturated organic acidssuch as methacrylic acid, acrylic acid, and itaconic acid; and ammoniumsalts such as tetramethyl ammonium chloride and tetrabutyl ammoniumchloride can be given. As examples of the base, aqueous ammonia;primary, secondary or tertiary aliphatic amines such as diethylamine,triethylamine, dibutylamine, and cyclohexylamine; aromatic amines suchas pyridine; sodium hydroxide, potassium hydroxide, and quaternaryammonium hydroxides such as tetramethylammonium hydroxide andtetrabutylammonium hydroxide can be given. Of these, preferable examplesare organic acids and unsaturated organic acids among the acids, andtertiary amines or tertiary ammonium hydroxides among the bases. Theamount of these acids or bases to be added is preferably from 0.001 to1.0 part by weight, and more preferably from 0.01 to 0.1 part by weight,for 100 part by weight of the alkoxysilane compounds. Any compoundswhich decompose upon irradiation of radioactive rays and initiate thepolymerization can be used as the radiation polymerization initiator ofthe component (C) in the present invention. A photosensitizer may beadded as required. The words “radiation” as used in the presentinvention include infrared rays, visible rays, ultraviolet rays, deepultraviolet rays, X-rays, electron beams, α-rays, β-rays, γ-rays, andthe like.

[0065] Given as specific examples of the above-mentioned radiationpolymerization initiators are acetophenone, acetophenone benzyl ketal,anthraquinone, 1-hydroxycyclohexylphenyl ketone,2,2-dimethoxy-2-phenylacetophenone, xanthone compounds, triphenylamine,carbazole, 3-methylacetophenone, 4-chlorobenzophenone,4,4′-dimethoxybenzophenone, 4,4′-diaminobenzophenone,2-hydroxy-2-methyl-1-phenylpropan-1-one,1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, xanthone,1,1-dimethoxydeoxybenzoin, 3,3′-dimethyl-4-methoxybenzophenone,thioxanethone compounds, diethylthioxanthone, 2-isopropylthioxanthone,2-chlorothioxanthone,1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one,2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one,triphenylamine, 2,4,6-trimethylbenzoyldiphenylphosphineoxide,bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide,bisacylphosphineoxide, benzyl dimethyl ketal, fluorenone, fluorene,benzaldehyde, benzoin ethyl ether, benzoin propyl ether, benzophenone,Michler's ketone,2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one,3-methylacetophenone, and3,3′,4,4′-tetra(t-butylperoxycarbonyl)benzophenone (BTTB). Combinationsof BTTB and a coloring matter photosensitizer such as xanthene,thioxanthene, cumarin, or ketocumarin can also be given as specificexamples of the initiator. Of these, benzyl dimethyl ketal,1-hydroxycyclohexyl phenyl ketone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide,bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentyl phosphine oxide,2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, and thelike are particularly preferred.

[0066] As examples of commercially available products ofphotoinitiators, Irgacure 184, 651, 500, 907, 369, 784, 2959, Darocur1116, 1173 (manufactured by Ciba Specialty Chemicals Co., Ltd.),Lucirine TPO (manufactured by BASF), Ubecryl P36 (manufactured by UCB),and Escacure KIP150, KIP100F (manufactured by Lamberti) can be given.

[0067] As examples of photosensitizers, triethylamine, diethylamine,N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid,methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, andisoamyl 4-dimethylaminobenzoate, as well as commercially availableproducts such as Ubecryl P102, 103, 104, 105 (manufactured by UCB), andthe like can be given.

[0068] The proportion of the photoinitiators used as the component (C)in the composition of the present invention is in the range preferablyfrom 0.01 to 10 wt %, more preferably from 0.5 to 7 wt %, andparticularly preferably from 1 to 5 wt %. If more than 10 wt %, storagestability of the composition and properties of the cured products may beadversely affected. If less than 0.01 part by weight, on the other hand,a cure speed may be retarded.

[0069] Polymerizable monomers having a vinyl group or (meth)acryloylgroup other than the above-mentioned component (A) can be used in thepresent invention as optional components. Such polymerizable monomersmay be either mono-functional monomers or poly-functional monomers.

[0070] Given as examples of mono-functional monomers are vinylgroup-containing monomers such as N-vinyl caprolactam, N-vinylpyrrolidone, N-vinylcarbazole, and vinylpyridine; acrylamide, acryloylmorpholine, 7-amino-3,7-dimethyloctyl (meth)acrylate, isobutoxymethyl(meth)acrylamide, isobornyloxyethyl (meth)acrylate, isobornyl(meth)acrylate, 2-ethylhexyl (meth)acrylate, ethyldiethylene glycol(meth)acrylate, t-octyl (meth)acrylamide, diacetone (meth)acrylamide,dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate,lauryl (meth)acrylate, dicyclopentadiene (meth)acrylate,dicyclopentenyloxyethyl (meth)acrylate, dicyclopentenyl (meth)acrylate,N,N-dimethyl(meth)acrylamide, tetrachlorophenyl(meth)acrylate,2-tetrachlorophenoxyethyl (meth)acrylate, tetrahydrofurfuryl(meth)acrylate, tetrabromophenyl (meth)acrylate,2-tetrabromophenoxyethyl (meth)acrylate, 2-trichlorophenoxyethyl(meth)acrylate, tribromophenyl (meth)acrylate, 2-tribromophenoxyethyl(meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl(meth)acrylate, phenoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate,pentachlorophenyl (meth)acrylate, pentabromophenyl (meth)acrylate,polyethylene glycol mono(meth)acrylate, polypropylene glycolmono(meth)acrylate, bornyl (meth)acrylate, and methyltriethylenediglycol (meth)acrylate.

[0071] Of these, N-vinyl caprolactam, N-vinyl pyrrolidone, acryloylmorpholine, N-vinylcarbazole, isobornyl (meth)acrylate, phenoxyethyl(meth)acrylate, and the like are preferred, with N-vinyl caprolactam,N-vinyl pyrrolidone, and acryloyl morpholine being particularlypreferred. The most preferred monofunctional polymerizable monomer isacryloyl morpholine.

[0072] As examples of commercially available products of thesemono-functional monomers, Aronix M-111, M-113, M-117 (manufactured byToagosei Co., Ltd.), Kayarad TC110S, R-629, R-644 (manufactured byNippon Kayaku Co., Ltd.), Viscoat 3700 (manufactured by Osaka OrganicChemical Industry Co., Ltd.), and the like can be given.

[0073] Given as examples of poly-functional monomers are (meth)acryloylgroup-containing monomers such as ethylene glycol di(meth)acrylate,dicyclopentenyl di(meth)acrylate, triethylene glycol diacrylate,tetraethylene glycol di(meth)acrylate, tricyclodecanediyldimethylenedi(meth)acrylate, tripropylene diacrylate, neopentyl glycoldi(meth)acrylate, both terminal (meth)acrylate of ethylene oxideaddition bisphenol A, both terminal (meth)acrylate of propylene oxideaddition bisphenol A, both terminal (meth)acrylate of ethylene oxideaddition tetrabromobisphenol A, both terminal (meth)acrylate ofpropylene oxide addition tetrabromobisphenol A, bisphenol A diglycidylether, both terminal (meth)acrylate of tetrabromobisphenol A diglycidylether, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate,polyester di(meth)acrylate, and polyethylene glycol di(meth)acrylate. Ofthese, both terminal (meth)acrylate of ethylene oxide addition bisphenolA, both terminal (meth)acrylate of propylene oxide addition bisphenol A,tricyclodecanediyldimethylene di(meth)acrylate, tetraethylene glycoldi(meth)acrylate, tripropylene glycol di(meth)acrylate, neopentyl glycoldi(meth)acrylate, and polyethylene glycol di(meth)acrylate arepreferred.

[0074] As commercially available products of poly-functional monomers,Yupimer UV, SA1002 (manufactured by Mitsubishi Chemical Corp.), Viscoat700 (manufactured by Osaka Organic Chemical Industry Co., Ltd.), KayaradR-604 (manufactured by Nippon Kayaku Co., Ltd.), Aronix M-210(manufactured by Toagosei Co., Ltd.), and the like can be used.

[0075] In addition to the above-described components, various additivescan be optionally added to the composition of the present invention.Given as examples of such additives are antioxidants, UV absorbers,light stabilizers, silane coupling agents, antioxidants, thermalpolymerization inhibitors, coloring agents, leveling agents,surfactants, preservatives, plasticizers, lubricants, solvents,inorganic fillers, organic fillers, wettability improvers, coatingsurface improvers, and the like. As commercially available products ofantioxidants Irganox 1010, 1035, 1076, 1222 (manufactured by CibaSpecialty Chemicals Co.), and the like can be given. As commerciallyavailable products of UV absorbers, Tinuvin P, 234, 320, 326, 327, 328,213, 400 (manufactured by Ciba Specialty Chemicals Co.), Sumisorb 110,130, 140, 220, 250, 300, 320, 340, 350, 400 (manufactured by SumitomoChemical Industries Co., Ltd.), and the like are given. As commerciallyavailable products of light stabilizers, Tinuvin 292, 144, 622LD(manufactured by Ciba Specialty Chemicals Co.), Sanol LS-770, 765, 292,2626, 1114, 744 (manufactured by Sankyo Chemical Co.), and the like canbe given. As silane coupling agents, γ-aminopropyl triethoxysilane,γ-mercaptopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane,and commercially available products such as SH6062, SZ6030 (manufacturedby Dow Corning Toray Silicone Co., Ltd.), KBE903, KBM803 (manufacturedby Shin-Etsu Silicone Co., Ltd.), and the like can be given. Ascommercially available products of aging preventives, Antigene W, S, P,3C, 6C, RD-G, FR, AW (manufactured by Sumitomo Chemical Industries Co.,Ltd.), and the like can be given. Polymers or oligomers such as epoxyresins, polymerizable compounds (such as urethane (meth)acrylate, vinylether, propenyl ether, maleic acid derivatives), polyamide, polyimide,polyamideimide, polyurethane, pblybutadiene, chloroprene, polyether,polyester, pentadiene derivatives, styrene/butadiene/styrene blockcopolymer, styrene/ethylene/butene/styrene block copolymer,styrene/isoprene/styrene block copolymer, petroleum resin, xylene resin,ketone resin, fluorine-containing oligomers, silicon-containingoligomers, polysulfide-type oligomers can also be incorporated in thecomposition of the present invention as other additives.

[0076] The radiation curable resin composition of the present inventioncan produce cured products with excellent characteristics such as a highrefractive index, superior abrasion resistance, transparency, chemicalresistance, and the like. The composition is thus suitable for use as ahard coat for plastic optical parts, touch panels, and film-type liquidcrystal elements, and fabricated plastic materials, and also as astain-proof or mar-proof coating material for floors and walls insidebuildings. In addition, because the composition does not produceinterference fringes when applied to a substrate with a similarrefractive index due to its high refractive index, the composition canbe used suitably in optical applications. When the radiation curableresin composition of the present invention is cured, cured products withpencil hardness from H to 9H at 23 can be obtained. The rate ofshrinkage upon curing is usually 10% or less, and preferably 6% or less.As mentioned above, the resulting cured products has a high refractiveindex, excellent abrasion resistance, transparency, chemical resistance,and the like. The cured products has preferably a refractive index of1.55 or more and light transmittance of 98% or more. Also, preferably anabout 5 μm thick layer of the composition, after cure, will have a lighttransmittance of at least 90%, and, after the Taber's abrasion test thatis set forth in this application, haze value of less than 40%.Therefore, the composition can be suitably used for plastic sheets,plastic films, and the like requiring transparency, and particularly asmaterials for optical use. Other application of the composition includescathode-ray tubes and front panels such as a flat display, laserdisplay, photochromic display, electrochromic display, liquid crystaldisplay, plasma display, light emitting diode display, andelectroluminescent panel, as well as parts for input equipment of thesefront panels. Other application includes front covers such as anenclosure case, lens for optical instrument, eye glass lens, windowshield, light cover, helmet shield, and the like. In addition, when acoating with a high refractive index is used as an optical material, itis desirable to provide a coating with a low refractive index to preventreflection.

EXAMPLES

[0077] The present invention will now be described in more detail by wayof examples which should not be construed as limiting the presentinvention. In the following examples, unless otherwise indicated,“parts” and “%” means respectively “parts by weight” and “wt %”.

Preparation of Alkoxysilane Compound Reference Example 1

[0078] 20.6 parts of isophorone diisocyanate was added dropwise to asolution consisting of 7.8 parts of mercaptopropyl trimethoxysilane and0.2 part of dibutyl tin dilaurate over one hour while stirring in dryair at 50. After stirring for a further 3 hours at 60, 71.4 parts ofpentaerythritol triacylate was added dropwise over one hour at 30. Themixture was stirred for an additional 3 hours with heating at 60 toobtain a compound having a polymerizable unsaturated group andalkoxysilane group in the molecule. This compound is herein designatedas “silane compound X”. The amount of residual isocyanate group in theproduct was analyzed. It was confirmed that the amount of residualisocyanate group was 0.1% or less, indicating that the reaction wascompleted almost quantitatively.

Preparation of the Component (B) Reference Example 2

[0079] A mixture of 8.1 parts of the silane compound X prepared inReference Example 1, 90.5 parts of zirconium oxide sol in methyl ethylketone solvent (number average particle diameter: 0.01 μm, zirconiumoxide concentration: 30%), and 0.1 part of ion exchanged water wasstirred for three hours at 60. After the addition of 1.3 parts of methylorthoformate and 41.2 parts of methyl ethyl ketone, the mixture wasstirred for a further one hour while heating at the same temperature toobtain a dispersion liquid of the reaction product of the compoundhaving a polymerizable unsaturated group and alkoxysilane group in themolecule and particles of zirconium. This dispersion liquid is hereindesignated as “dispersion b1”.

Reference Example 3

[0080] A mixture of 8.1 parts of the silane compound X prepared inReference Example 1, 90.5 parts of antimony pentoxide sol in methylethyl ketone solvent (number average particle diameter: 0.05 μm,antimony pentoxide concentration: 30%), and 0.1 part of ion exchangewater was stirred for three hours at 60. After the addition of 1.3 partsof methyl ortho-formate and 41.2 parts of methyl ethyl ketone, themixture was stirred for a further one hour while heating at the sametemperature to obtain a dispersion liquid of the reaction product of thecompound having a polymerizable unsaturated group and alkoxysilane groupin the molecule and particles of antimony pentoxide. This dispersionliquid is herein designated as “dispersion b2”. A solid content (%) ofthis dispersion liquid was 25%.

Reference Example 4

[0081] A mixture of 8.1 parts of the silane compound X prepared inReference Example 1, 100 parts of alumina sol in methanol (numberaverage particle diameter: 0.0075 μm, solid content: 30%, water content:5.6%), and 0.01 part of p-methoxy phenol was stirred for three hours at60. After the addition of 1.3 parts of methyl orthoformate and 41.2parts of methanol, the mixture was stirred for a further one hour whileheating at the same temperature to obtain a dispersion liquid of thereaction product of the compound having a polymerizable unsaturatedgroup and alkoxysilane group in the molecule and alumina particles. Thisdispersion liquid is herein designated as “dispersion b3”. A solidcontent (%) of this dispersion liquid was 25%.

Preparation of compositions

[0082] Preparation of the composition used in the present invention willnow be described. The ratio by weight of each component is shown inTable 1.

Example 1

[0083] 80 parts of the dispersion liquid b1 prepared in ReferenceExample 2 as the component (B), 20 parts of dipentaerythritolhexacrylate as the component (A), 1.2 parts of 1-hydroxycyclohexylphenyl ketone and 0.8 parts of 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one as the component (C) were placed in a containershielded from ultraviolet rays and the mixture was stirred for 30minutes at room-temperature to obtain the composition shown in Table 1as a homogeneous solution. The compositions for Example 2-5 andComparative Examples 1-3 shown in Table 1 were prepared in the samemanner. The compositions of Examples 1 and 3 correspond to thecompositions of Comparative Examples 2 and 3 respectively. Thecompositions of Examples 2 and 4 and Comparative Example 1 contain alarge amount of the component (B) to increase the refractive index.TABLE 1 Parts (parts of solid components) Comparative Example Example 12 3 4 5 1 2 3 Component (A) Unsaturated organic compound 20 8 20 12 1220 20 (Dipentaerythritol hexacrylate) Metal oxide sol solution withoutsilane treatment Zirconia sol 80 (20) Antimony oxide sol 80 (20)Component (B) Metal oxide sol solution with silane treatment 80 92 b1(20) (32) 100 80 88 (40) b2 (20) (28) b3 80 (20) Component (C)*1-hydroxycyclohexyl phenyl 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 ketone*2-methyl-1-[4-(methylthio) 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8phenyl]-2-morpholinopropan-1- one Total 102 102 102 102 94 102 102 102Solid components (%) 41 41 41 41 36 41 41 41 Metal oxide in the solid 3861 38 53 46 76 50 50 components (wt%)

Test Examples

[0084] Test specimens were prepared using the resin compositionsprepared in the above Examples and Comparative Examples to evaluatepencil hardness, mar resistance, abrasion resistance, adhesion tosubstrates, transmittance, and refractive index of the cure filmsaccording to the following methods. The results are shown in Table 2.

[0085] Preparation of test specimens:

[0086] The resin compositions prepared in the above Examples andComparative Examples were applied on a commercially available PET film(thickness: 188 μm) using a wire bar coater (No. 10) to a thickness ofabout 5 μm. The coatings were allowed to stand for one minute in aninfrared dryer oven at 40, followed by irradiation with ultraviolet raysat a dose of 0.3 J/cm² in the air to obtain cured coating films. Thecured films were then allowed to stand at 23 and relative humidity of50% for 24 hours to obtain test specimens.

[0087] Appearance:

[0088] The appearance was evaluated by naked eye observation.

[0089] Light transmittance:

[0090] Light transmittance at a wavelength of 500 nm was measured usinga spectrophotometer and corrected for reflectance and transmittance ofthe substrates.

[0091] Refractive index:

[0092] The refractive index was measured by Abbe's refractometer.

[0093] Pencil hardness:

[0094] The pencil hardness was measured according to JIS K5400 using apencil scratch tester.

[0095] Abrasive resistance:

[0096] A haze value (H) after the Taber's abrasion test (abrasive wheelCS-10F, load 500 g, rotation 100) was measured using a Taber's abrasiontester according to JIS R3221.

[0097] Substrate adhesion:

[0098] JIS K5400 was followed. 100 squares (1 mm×1 mm) were produced onthe surface of the cured test specimen by 11×11 cross-cut lines. Acommercially available cellophane tape was adhered and rapidly peeledoff. The substrate adhesion was indicated by X/100, wherein X is thenumber of squares left on the substrate without being detached. TABLE 2Example Comparative Example 1 2 3 4 5 1 2 3 Appearance Trans- Trans-Trans- Trans- Trans- Trans- Semi- Opaque parent parent parent parentparent parent trans- parent Light transmittance (/%) 99 99 100 100 97100 89 63 Refractive index 1.595 1.645 1.555 1.566 1.560 1.585 1.641 —Pencil hardness 3H 2H 3H 2H 3H H 3H 3H Haze value of coating film 0.50.6 0.5 0.5 0.6 0.6 4.4 6.8 (%) Taber's test* 28 22 28 31 8 49 27 46Adhesion** 100 100 100 100 100 100 100 100

Effect of the Invention

[0099] The radiation curable resin composition of the present inventioncan produce cured products with excellent characteristics such as a highrefractive index, superior abrasion resistance, transparency, chemicalresistance, and the like. The composition is thus suitable for use as ahard coat for plastic optical parts, touch panels, and film-type liquidcrystal elements, and fabricated plastic materials, and also as astain-proof or mar-proof coating material for floors and walls insidebuildings. In addition, because the composition does not producereflection interference stripes when applied to a substrate with asimilar refractive index due to its high refractive index, thecomposition can be used suitably in optical applications.

1. A radiation-curable metal particle comprising a radiation-curablegroup linked by a silyl group to a metal.
 2. The particle according toclaim 1, wherein said metal is selected from the group consisting ofzirconium, tatinium, antimony, zinc, tin, indium, cerium and aluminium.3. The particle according to any one of claims 1-2, wherein the silylgroup is a substituted silyl group which comprises an alkoxy group, aurethane group and/or a thiourethane group.
 4. The particle according toany one of claims 1-3, wherein said particle is obtainable by reactingan organosilicon compound with a metal oxide.
 5. The particle accordingto any one of claims 1-4, wherein the particle has a diameter of from0.001 to 2 μm.
 6. A method for forming a radiation-curable metalparticle according to any one of claims 1-5, comprising reacting a metaloxide with an organosilicon compound.
 7. The method according to claim6, wherein the metal oxide is reacted with the organosilicon compound inthe presence of an acid or a base.
 8. A radiation-curable compositioncomprising: (A) a (meth)acrylic compound; (B) metal particles accordingto any one of claims 1-6; and (C) a radiation polymerizationphotoinitiator.
 9. The composition according to claim 8, wherein said(meth)acrylic compound comprises at least three (meth)acryloyl groups.10. The composition according to any one of claims 8-9, wherein an about5 μm thick layer of the composition, after cure, has a lighttransmittance of at least 90% and a haze value after the Taber'sabrasion test of less than 40%.
 11. A product formed from curing thecomposition according to any one of claims 8-10, wherein said producthas a refractive index of at least 1.55 and a light transmittance of atleast 95%.
 12. The product according to claim 11, wherein said productsis a coating.
 13. An anti-reflection article comprising the productaccording to any one of claims 11-12.